Least Reliable Water Systems in America — 2026

Out of 42,670 ZIP codes with data across all 50 states, these are the lowest-ranked areas for reliability score. Each ZIP links to a full safety report with water quality, lead, radon, and flood data.

Statistic	Value
ZIP codes ranked	42,670
Lowest value	10/100
Median value	70/100

100 Lowest-Ranked ZIP Codes

Rank	ZIP Code	City	State	Reliability Score	Safety Score
1	03307	Loudon	NH	10/100	40/100
2	04664	Sullivan	ME	10/100	33/100
3	04677	Sorrento	ME	10/100	33/100
4	06241	Dayville	CT	10/100	41/100
5	06258	Pomfret	CT	10/100	50/100
6	06279	Willington	CT	10/100	66/100
7	06331	Canterbury	CT	10/100	66/100
8	10980	Stony Point	NY	10/100	60/100
9	11202	Brooklyn	NY	10/100	62/100
10	11240	Brooklyn	NY	10/100	62/100
11	11241	Brooklyn	NY	10/100	62/100
12	11242	Brooklyn	NY	10/100	62/100
13	11243	Brooklyn	NY	10/100	62/100
14	11244	Brooklyn	NY	10/100	62/100
15	11245	Brooklyn	NY	10/100	62/100
16	11247	Brooklyn	NY	10/100	62/100
17	11248	Brooklyn	NY	10/100	62/100
18	11251	Brooklyn	NY	10/100	62/100
19	11252	Brooklyn	NY	10/100	62/100
20	11254	Brooklyn	NY	10/100	62/100
21	11256	Brooklyn	NY	10/100	62/100
22	12430	Fleischmanns	NY	10/100	41/100
23	23424	Rescue	VA	10/100	70/100
24	25410	Bakerton	WV	10/100	45/100
25	30807	Camak	GA	10/100	66/100
26	48438	Goodrich	MI	10/100	58/100
27	51540	Hastings	IA	10/100	47/100
28	56253	Lake Lillian	MN	10/100	45/100
29	59430	Denton	MT	10/100	45/100
30	59542	Turner	MT	10/100	22/100
31	67024	Cedar Vale	KS	10/100	58/100
32	67066	Iuka	KS	10/100	33/100
33	67478	Simpson	KS	10/100	37/100
34	67575	Rush Center	KS	10/100	45/100
35	67581	Sylvia	KS	10/100	58/100
36	67585	Yoder	KS	10/100	50/100
37	67657	Palco	KS	10/100	3/100
38	67837	Copeland	KS	10/100	33/100
39	67842	Ford	KS	10/100	45/100
40	68324	Burr	NE	10/100	33/100
41	68440	Steele City	NE	10/100	24/100
42	68710	Allen	NE	10/100	22/100
43	68865	Phillips	NE	10/100	38/100
44	68935	Edgar	NE	10/100	33/100
45	71247	Hodge	LA	10/100	82/100
46	71432	Georgetown	LA	10/100	65/100
47	73033	Eakly	OK	10/100	55/100
48	73559	Mountain Park	OK	10/100	70/100
49	74001	Avant	OK	10/100	70/100
50	74422	Boynton	OK	10/100	55/100
51	74636	Deer Creek	OK	10/100	66/100
52	74637	Fairfax	OK	10/100	70/100
53	74756	Sawyer	OK	10/100	66/100
54	74837	Cromwell	OK	10/100	66/100
55	76937	Eola	TX	10/100	55/100
56	78369	Mirando City	TX	10/100	70/100
57	78828	Barksdale	TX	10/100	66/100
58	79227	Crowell	TX	10/100	66/100
59	79255	Quitaque	TX	10/100	55/100
60	79261	Turkey	TX	10/100	55/100
61	79367	Smyer	TX	10/100	39/100
62	79377	Welch	TX	10/100	66/100
63	79380	Whitharral	TX	10/100	39/100
64	79505	Benjamin	TX	10/100	55/100
65	79713	Ackerly	TX	10/100	72/100
66	79738	Gail	TX	10/100	55/100
67	79785	Toyah	TX	10/100	57/100
68	83633	King Hill	ID	10/100	33/100
69	84317	Huntsville	UT	10/100	43/100
70	85632	San Simon	AZ	10/100	58/100
71	87560	Ribera	NM	10/100	46/100
72	87569	Serafina	NM	10/100	33/100
73	91903	Alpine	CA	10/100	69/100
74	91931	Guatay	CA	10/100	33/100
75	91963	Potrero	CA	10/100	55/100
76	91990	Potrero	CA	10/100	55/100
77	92365	Newberry Springs	CA	10/100	50/100
78	93285	Wofford Heights	CA	10/100	58/100
79	93643	North Fork	CA	10/100	50/100
80	93644	Oakhurst	CA	10/100	57/100
81	93669	Wishon	CA	10/100	35/100
82	94570	Moraga	CA	10/100	45/100
83	01921	Boxford	MA	13/100	49/100
84	33114	Coral Gables	FL	13/100	85/100
85	33446	Delray Beach	FL	13/100	75/100
86	77413	Barker	TX	13/100	90/100
87	79021	Cotton Center	TX	13/100	54/100
88	92266	Palo Verde	CA	13/100	80/100
89	02725	Somerset	MA	15/100	42/100
90	02726	Somerset	MA	15/100	37/100
91	02766	Norton	MA	15/100	53/100
92	04414	Brownville	ME	15/100	49/100
93	04863	Vinalhaven	ME	15/100	58/100
94	06281	Woodstock	CT	15/100	46/100
95	07828	Budd Lake	NJ	15/100	50/100
96	08850	Milltown	NJ	15/100	56/100
97	10504	Armonk	NY	15/100	60/100
98	10506	Bedford	NY	15/100	65/100
99	10507	Bedford Hills	NY	15/100	65/100
100	10536	Katonah	NY	15/100	65/100

Rankings by State

State	ZIP Codes Ranked
Texas	2,728
California	2,674
New York	2,261
Pennsylvania	2,249
Florida	1,669
Illinois	1,610
Ohio	1,453
Virginia	1,273
Missouri	1,194
Michigan	1,179
North Carolina	1,132
Iowa	1,064
Minnesota	1,023
Kentucky	994
Georgia	987
Indiana	986
West Virginia	938
Wisconsin	902
Alabama	845
Louisiana	801
Tennessee	792
Oklahoma	774
New Jersey	769
Kansas	755
Massachusetts	742
Washington	732
Arkansas	711
Colorado	660
Maryland	630
Nebraska	625
South Carolina	565
Mississippi	564
Arizona	556
Maine	504
Oregon	483
Connecticut	442
New Mexico	429
North Dakota	413
Montana	408
South Dakota	397
Utah	350
Idaho	324
Vermont	312
District of Columbia	286
New Hampshire	284
Alaska	274
Nevada	254
Wyoming	195
Hawaii	141
Delaware	95
Rhode Island	93

Methodology

Water system reliability scores (0-100) combine violation frequency, violation recency, resolution rate, and system size. Systems with repeated health-based violations and unresolved issues score lowest. The reliability score focuses specifically on the water utility performance, distinct from the broader Home Safety Score.

Data sources: EPA Safe Drinking Water Information System (SDWIS), FEMA National Flood Insurance Program, EPA radon zone maps, EIA electricity rates, and Consumer Confidence Reports. Last updated: 2026-06-04.

Frequently Asked Questions

What does a low water reliability score mean?

A low reliability score (below 50) indicates a water system with frequent violations, poor resolution rates, or recurring compliance issues. These systems may have aging infrastructure, inadequate treatment, or management challenges.

How is reliability different from safety score?

The reliability score focuses specifically on the water utility performance (violations, resolution, compliance). The Home Safety Score is broader, also including lead risk, radon, and flood data. A ZIP code can have a reliable water system but still have high radon or flood risk.